I did an experiment in which I dropped three different sized spherical beads (4mm, 6mm, and 11mm diameter) with the same densities through a viscous liquid (a water-detergent solution). They all fell the same distance, but the biggest one fell a full ten seconds faster than the smallest one. What could be the explanation for this? I would have thought the opposite due to friction and the fact that gravity affects everything the same. Why did the biggest one fall fastest?